This invention relates to a two part endless conveyor which is adjustable between an operative position in which one conveyor part forms a prolongation of the other conveyor part, and a folded transport position in which the two conveyor parts extend generally parallel to, and are located one above the other.
Endless conveyor belts have many uses, in order to convey material from one place to another, but a requirement for a folding facility is usually only necessary to be provided on apparatus which is intended to be transported from one site to another. Thus, a transportable apparatus has an operative state in which any endless conveyors provided thereon may project from the apparatus in order to discharge material to deposition zones spaced from the apparatus, but which can be folded to transport positions in which the overall length and/or height of the apparatus is reduced i.e. the overall xe2x80x9cenvelopexe2x80x9d of the apparatus is reduced in size so as to render the apparatus suitable for being transported from one site to another. Transport may be via a low loader, or via a fifth wheel coupling in the case of a wheeled apparatus.
The invention has been developed primarily in connection with a two part endless conveyor which is intended to be mounted on the frame of a transportable material treatment (processing/handling) apparatus, such as a mobile screening and/crushing plant, and which is operative when in a deployed mode to discharge treated material to a required deposition zone.
In the case of a screening plant, it is usual to have one or more discharge conveyor which can be adjusted between an operative position in which it projects rearwardly, or to one side of the apparatus (usually referred to as a xe2x80x9ctail conveyorxe2x80x9d or a xe2x80x9cside conveyorxe2x80x9d respectively), but which can be folded so as to take up a transport position in which the overall envelope of the apparatus (including the discharge conveyor(s)) is reduced in size so that the apparatus can be transported along a public highway.
In the case of a tail conveyor, it is known to design the conveyor in two parts, of which a first part (the head part) is pivotally mounted on the frame of the apparatus so as to be adjustable to an operative position in which any required upward and rearward inclination of the entire conveyor can be set, so that a stockpile of material can be formed rearwardly of the apparatus. The tail conveyor also has a second part (the tail part) which forms a prolongation of the first part in the operative position, but can be folded to a transport position in which one part overlies the other part. In the transport position, it may be the tail part overlying the head part, or vice versa.
The head part may also be downwardly adjustable about its pivotable mounting on the frame, in the transport position, in order to further reduce the overall height of the conveyor, as well as to reduce its overall length when the two conveyor parts are folded to the transport position.
The present invention is primarily concerned with an improved folding mechanism which is operative to adjust a two part discharge conveyor of a mobile material treatment apparatus between a transport position and a deployed position. However, it should be understood that the improved folding mechanism of the invention has general application to a two part endless conveyor for use in other suitable apparatus.
According to the invention there is provided a two part endless conveyor which is adjustable between an in-line operative position, and a folded transport position, and which comprises:
a first conveyor part which is adapted to be mounted at a first end on the frame of a material handling apparatus;
a second conveyor part which is adjustably mounted at a first end on an opposite second end of the first conveyor part for movement between an operative position in which the second conveyor part forms a prolongation of the first conveyor part and so that the opposite second end of the second conveyor part forms a discharge end of the conveyor, and a transport position in which one of the conveyor parts underlies the other conveyor part and extends generally parallel thereto; and
a folding mechanism which interconnects the second end of the first conveyor part to the first end of the second conveyor part, said mechanism comprising:
a coupling block or linkage which interconnects the second end of the first conveyor part and the first end of the second conveyor part via respective ones of a pair of pivot connections; and
a pair of linear actuators each associated with a respective conveyor part and extending between a mounting point on the conveyor part and the coupling block, each actuator being operative to rotate the coupling block through approximately 90xc2x0 about the respective pivot connection whereby the folding mechanism, under the action of the two linear actuators, can adjust the first and second conveyor parts between the in-line operative position and the folded transport position.
The folding mechanism therefore provides a coupling block which is relatively rotatable through approximately 90xc2x0 relative to the second end of the first conveyor part via a respective pivot connection, and also is rotatable relatively through approximately 90xc2x0 about a respective pivot connection to the first end of the second conveyor part. Therefore, with a relatively simple construction, the two conveyor parts can be readily adjusted between the operative or deployed position, and the folded transport position, in which the overall length of the conveyor is substantially reduced, while at the same time taking up relatively small space, since the conveyor parts are arranged one above the other, and generally parallel to each other.
A two part endless conveyor according to the invention therefore is particularly suitable for use as a discharge conveyor, and more particularly a tail conveyor mounted below a screening plant on a mobile screening apparatus, in which space is available below the screening plant which can be occupied by the tail conveyor when folded to its transport position.
In a preferred arrangement, the first conveyor part is the head part of a tail conveyor, and which is adapted to be pivotally mounted on the frame of the screening apparatus, and can be pivoted about its mounting point in order to set any required overall inclination of the tail conveyor when in the deployed position, so that the second end of the second conveyor part (the tail part) is at a required height so that a stockpile of screened material can be formed at a required location spaced from the apparatus.
An endless conveyor has an upper conveyor run and a lower conveyor run, and it is usual to provide guide or transfer rollers which facilitate the movement of the belt along an endless path. Evidently, when the two conveyor parts are folded to the transport position, this has an effect on the endless belt, and it is therefore preferred that a guide arrangement be provided in the general region of the connection between the two conveyor parts, and which is able to guide the lower conveyor run, during the folding movement, and also when the folded transport position is reached, so as to apply tension to the lower conveyor run, and thereby at least minimise the risk of slack portions of the conveyor belt being formed. Conveniently, the guide arrangement comprises a roller mounted on the coupling block, and which is engagable with the lower conveyor run, both in the operative position, and in the transport position, and during adjustment movement of the conveyor parts.
Any suitable linear actuator may be provided, to interact between each conveyor part and a suitable connection point with the coupling block, although it will be preferred to use a piston/cylinder device, and preferably a hydraulically operated device.
The piston cylinder devices may be arranged in a common hydraulic circuit, in parallel with each other, or may have separate hydraulic circuits. The devices may operate in sequence i.e. independently of each other, or simultaneously.